Method of sizing cellulose fibers



Patented Oct. 27,1925.

UNITED STATES PATENT OFFHIE.

JUDSON"A. DE CEW, O'F MOUNT VERNON, .NEW YORK, ASSIGNOR TO" PROCESS ENGI- NEERS INCL, OF NEW YORK, N. Y.

METHOD OF SIZING GELLULOSE FIBERS.

No Drawing.

To all whom it may concern:

Beit known that ,JUDSON A. Du CEW, a citizen of the United States, residing at Mount Vernon, in the county of \Vestchester and State of New York, has invented certain new and useful Improvements in Methods of Sizing Cellulose l ibers, of which the following is a specification.

Engine sizing of machine made paper by means of rosin size and sulphate of alumina is carried on in the beating engine or mixer. Sometimes the alum is added before the size and sometimes the size is added to the paper stock before the alum.

The size is always coagulated by means of .the alum before the heater is discharged.

After the stock leaves the beater, it is passed through a heating or grinding engine, called a jordan, where a violent heating action is given to the mass.

The coagulated sizing material is in a very highly dispersed and hydrated condi- 1 tion when it is freshly precipitated but as it passes through the jordan in the presence of excess of sulphate of alumina, the violent beating action has a strong dehydrating action on the alumina and rosin hydrates. Moreover, the sizing material that is precipitated upon the surface of the fibers will be scraped off and left as a filling material between the fibers.

The discovery of this fact explains why the sizing from the paper machine is never as"eflic1ent as that carried out by means of laboratory tests.

Another disadvantage of the present method of operation is the amount of cor- .rosion that always takes place in the ordan Application filed June 7, 1924. Serial No. 718,657.

engine from the presence of sulphate of alumina in the stock. This means rapid. wearing down of the knives and. constant replacements.

I have discovered thatthese disadvantages can be avoided by not precipitating the size until the stock has passed through the jordan engine and is ready for the paper machine, and in this way a fresh highly hydrated precipitate is formed which has great covering power and sizing value.

My method of operation is to add the rosin size to the beating engine and coagulate it after it leaves the jordan by bringmg an alum. solution into contact with the stock in the pipes or machine chest. I may also do all of the sizing in a separate chest after the stock comes from the jordan.

By this method chemical impurities do not injure the sizing'to the same extent as they do, when the precipitated size is subjected to dehydration. influences.

hat I claim as my invention is:

1. The method of sizing paper which consists in withholding the precipitation of the rosin until after the beating action of the jordan engine is complete.

2. The method of sizing paper which con; sists in adding the rosin size to the beating engine and co-agulating said size after the paper stock has passed through the jordau.

3. The method of producing with paper pulp an undehydrated precipitate of rosin and alumina which consists in adding the onson A. DE tinw. 

